Toyota and Ford: “It’s the software, stupid!”

As Toyota’s ongoing troubles start to resemble a slow-moving train wreck, one thing is becoming apparent: these guys make some very sophisticated hardware, but they’re yet to master tying it all together with software.

Debugging Your Car

The Prius brake problems are the case in point. Drivers have complained that the brakes on the 2010 Prius momentarily stopped working at low speeds, especially on slippery surfaces. Toyota said Thursday a software glitch is to blame for braking problems in the 2010 model. They’ll offer a software update.

The Prius and other hybrids increasingly rely on complex electronics to combine the regenerative braking with brake pads, so that battery recharging absorbs as much energy as possible. Getting regenerative braking, ABS brakes and conventional brakes to work together turns out to be a non-trivial problem.

This is the kind of software bug that you don’t fix retroactively with an emailed service pack. I can see a popup window on my LCD dashboard via a wireless link: “Updates are available for your car. Click here to download and install 2010 Prius SP3. Reboot may be required after installation.” Click download and look for a coffee shop where you can hang out while your car roboots. Let’s hope all the CAN and LIN bus drivers still work.

Meanwhile Back in Detroit…

Meanwhile, Ford Motor said Thursday that there was a problem with the brakes of the hybrid version of the Ford Fusion. Ford said customers could receive a free software update, but it did not begin a formal recall.

Ford said the problem in its Fusion was caused by the car’s unnecessarily switching between its conventional brakes and the regenerative brakes, which absorb energy while braking to charge the battery. The Prius also uses regenerative braking. According to the L.A. Times,

Ford said a software glitch on Ford Fusion and Mercury Milan hybrids built on or before Oct. 17 could cause drivers to perceive a loss of braking as the car shifts unnecessarily from regenerative braking into the conventional mode.

While Consumer Reports was test driving a Ford Fusion, brake failure almost caused an accident:

Consumer Reports said that with the regenerative braking disengaged, as happened in the incident near their track, the brake pedal needed to be pushed more than an inch farther down to engage the conventional brakes.

System-Level Design

As cars become increasingly computerized, these sorts of problems will become more common. There are a number of stringent standards that hardware manufacturers must meet to qualify for inclusion in automotive systems, but there is no similar “automotive qual” for software of which I’m aware (correct me if I’m wrong). There certainly doesn’t appear to be in any case.

This is one area where the immaturity of system-level design tools is a lot more than a nuisance—it’s outright dangerous. No extremely complex system is going to be completely bug free, but it’s imperative that none are released before all the “A-level” bugs are identified and eliminated.

The Prius and Ford Fusion problems are a red flag for the automotive industry. They need to get on top of the software and systems or there will be big trouble farther down the road.